In recent years, a grave problem arises in medical and social fields in that patients with lifestyle-related diseases increase as diets are westernized. Currently, it is reported that there are eight million diabetic patients and there are twenty million diabetes-related people when would-be diabetic patients are included. Three major complications of diabetes are “retinopathy, nephropathy, and neuropathy”, and the diabetes develops as a factor of arteriosclerosis, and thus there is a concern that the diabetes will develop to a heart disease or a brain disease.
The diabetes develops when a function of the pancreas is degraded due to disorder of a diet habit or a lifestyle, an influence of secretions from adipose cell because of obesity, and oxidative stress, and then an amount of insulin that controls a blood glucose level is insufficient, or efficacy of the insulin is lowered. The diabetes brings about symptoms of an increase in the number of times or an amount of urination, a dry throat, or the like; however, the symptoms do not develop to a subjective symptom of a disorder, and thus the diabetes are mostly diagnosed through an examination in a hospital or the like. This is why there are many “silent” diabetic patients.
When abnormal symptoms appear due to the complications and are examined in a hospital or the like, disease conditions are already developed in many cases, and thus it is difficult to completely cure the disease. In particular, it is often difficult to perform medical treatment on the complications, and thus it is important to prevent diabetes, similarly to other lifestyle-related diseases. In order to perform the prevention, it is inevitable to recognize the diabetes early and to determine treatment effects. In this respect, there are many examination methods of the diabetes.
Under a condition in which there are an abnormal amount of carbohydrates or lipids in blood, application of oxidative stress results in a reaction between proteins and the carbohydrates or the lipids, and advanced glycation endproducts (AGEs) are produced. The AGEs are end products that are formed in a nonenzymatic glycosylation reaction (Maillard reaction) of proteins, have a yellowish brown color, are substances which emit fluorescence, and have a property of being linked to proteins in the vicinity thereof and forming cross-linkage.
The AGEs are known to be deposited or infiltrate in blood vessel walls, or to cause inflammation by acting on macrophages which are a part of an immune system and releasing cytokines as a kind of proteins, and thus to induce arteriosclerosis.
In the case of the diabetes, the AGEs increase as the blood glucose increases. Therefore, monitoring of the AGEs makes it possible to recognize diabetes early or to find a development state. As described above, as a method for screening diabetes mellitus by monitoring the AGEs, for example, a method disclosed in PTL 1 is reported.
In the method, the skin on a forearm is illuminated with excitation light, a fluorescence spectrum from the AGEs linked to skin collagen is measured, and the measured fluorescence spectrum is compared to a predetermined model. In this manner, the AGEs are monitored. As described above, data of the AGEs are acquired without invasion.